Bioluminescence and chemiluminescence abilities of trans ‐3‐hydroxyhispidin on the luminous fungus Mycena chlorophos

The fungus Mycena chlorophos emits green light from its pileus gills but not from its stipes. The chemical mechanisms underlying its bioluminescence are unclear. Trans ‐3‐hydroxyhispidin has been known to be a luminescence substrate for the bioluminescent mycelia of Neonothopanus nambi and N. gardneri . In the present study, the bioluminescence and chemiluminescence abilities of trans ‐3‐hydroxyhispidin on pileus gills and originally non‐bioluminescent stipes of M. chlorophos were demonstrated. Trans‐ 3‐hydroxyhispidin induced bioluminescence of living gills and stipes. The bioluminescence spectra of living gills and stipes measured after the addition of trans ‐3‐hydroxyhispidin were consistent with the original bioluminescence spectrum of gills. Frozen–thawed (dead) gills and stipes maintained trans ‐3‐hydroxyhispidin luminescence activity, and the luminescence‐active enzyme (luciferase) was partially purified in the water‐insoluble state from both tissues using gel filtration followed by ultracentrifugation. The optimum temperature of the chemiluminescence reactions of trans ‐3‐hydroxyhispidin in the presence of partially purified gill or stipe luciferase was 25°C. The chemiluminescence quantum yields of trans ‐3‐hydroxyhispidin for gill luciferase and stipe luciferase in 20 mM phosphate buffer at 25°C were 0.017 and 0.00096, respectively and the chemiluminescence spectra were almost consistent with the bioluminescence spectrum of living gills. These results indicate that trans ‐3‐hydroxyhispidin can be a candidate as a substrate for M. chlorophos bioluminescence.